Well, looks like I got burned, so to speak! I've been burning some buckwheat size coal from GregL since Sunday mid day, and up until last night, it was running beautifully.

Went to bed around 10 last night, everything was running fine - but then I woke up at 12:30am to the most awful stench in the house . I ran downstairs to see what was going on and at first glance, the stove looked normal, but a second look around the back showed where I could see glowing heat at the hopper/stoker interface. Oh SH!T!

I spent the next couple of hours digging out the hopper and pushing the burning coal down the grate and into the ash bucket. I pulled off the hopper and started taking the stoker apart. The nylon cam was a puddle of goo, and the nylon screws were in a similar condition. The felt insulation sheet between the stoker and the gear motor mount was well crisped, and was responsible for much of the stench. Probably a good thing as that is what woke me up. Fortunately, there doesn't appear to be any other damage or discoloration due to the heat, and the stoker motor is fine.

The CO detector which is 12 feet away never registered any CO (digital display), and there wasn't even any coal gas smell - the direct vent was sucking all the fumes into the stove. All I could smell were toasty stoker parts.

I called Keystoker this morning to order a new cam - and discussed the problem. They stated that buck shouldn't be burned in a direct vent stove (and Don had told me that once before, also). Of course, being the smarty pants, I thought I had this stove dialed in perfectly with the draft, etc. so why should it make a difference between DV or regular vent? Well, obviously it does, and with the larger coal size, it was able to pull enough air down through the hopper to let the fire burn back. With the rice coal, it never even hinted at trying to burn back.

It also doesn't help that the stove idles much of the time, which gave the fire the time to burn back. At higher fire rates, the coal would likely be pushed down faster than it could burn back..

So, I'm down until my cam gets here, and will have to mix the buck in with the rice to avoid duplicating this scenario. Live (a good thing) and learn....

I ran both Buck & Rice together when it was really cold to prevent the Clinkers forming of it burning so hot (of course, no baro damper at the time). BUT, that was without the Direct Vent, just the chimney.

I now have it hooked to the DV and it seems to be burning fine so far. But I am only running Rice and hasn't gotten real cold (20's).

Sorry to hear about it, glad you were home and could get it stopped.

Sidenote: I had some sulfur smell in my garage from my Keystoker since I re-hooked it back up last weekend, the CO's didn't register anything ( I think min. is around 20-30 PPM before they alarm), but you could smell faint exhaust gases....I figured since it was windy, it may have just been blowing some back around the windows or something, but seemed like it wouldn't go away.

I finally put some aluminum tape on all the joints (elbow's, TEE';s, etc..) and FINALLY got the smell to go away. I think I had a bad seal on one of the connections....MUCH better now.

I'll have to run the buck and rice together, also. I just can't imagine why the DV makes any difference whether it will run buck or not, but I guess it does. Not a big deal for me as my local supplier carries the rice, and the buck was a 'test' from GregL.

I've had a real faint smell of coal gas also since getting the stove running, but it's very VERY faint and intermittent. I think it's coming from the blower housing area on the DV. I'll pull it apart after the season and regasket and seal it all. It's not enough to worry about at this time.

Just a note, not really related to the hopper fire topic, but the coal gas topic.Last year before I installed the baro damper the stove would get hot and since a lot of the heat was going up the chimney I would get a coal combustion smell in the house, I finally figured out what was causing it, the pipes expanding and any gaps opening up. With the baro damper-not such problem.